Answer:
The answer to your question is: I bought 7 snacks
Step-by-step explanation:
Data
beginning balance = $42 = b
lunch = $1.80 = l
snack = $ 0.85 = s
final balance = $0.05 = f
f = b - 1.8l - 0.05s
0.05 = 42 - 1.8l - 0.85s
After 20 days I spent = 1.8(20) in lunches = $36
0.05 = 42 - 36 - 0.85s
0.05 = 6 - 0.85s
0.05 - 6 = -0.85s
-5.95 = -0.85s
s = -5.95/-0.85
s = 7
2000 x 2 x 0.02 = 80
answer
interest will be $80
